Method of producing semiconductor package, apparatus for producing semiconductor package, and adhesive film

ABSTRACT

A method of producing a semiconductor package enabling a sheet-like adhesive film to be used as it is and thereby reducing loss and enabling mounting without the piece of adhesive film sticking out from the semiconductor chip, comprising forming cutting-off notches in an adhesive film provided on a support film from the adhesive film side down to the surface of the support film or a depth D in the middle and cutting the adhesive film to pieces of predetermined size, then stretching the support film to separate the cut individual piece of the adhesive film, attaching semiconductor chip to the cut individual piece of the adhesive film, and mounting the semiconductor chip on a substrate by the piece of adhesive film, and an apparatus for producing a semiconductor package and adhesive film for use with that method.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of producing a semiconductorpackage, an apparatus for producing a semiconductor package, and anadhesive film, more particularly relates to a method of producing asemiconductor package called “system-in-package (SiP)” and an apparatusfor producing a semiconductor package and an adhesive film used for thesame.

2. Description of the Related Art

Demand for reducing the size, thickness, and weight of digital videocameras, digital mobile phones, notebook computers, and other portableelectronic devices has been growing increasingly stronger. To meet withthis, VSLIs and other semiconductor packages have been reduced 70% insize in the past three years. On the other hand, how to raise themounting density of components on mounting boards (printed circuitboards) has been the subject of much R&D for electronic circuit devicescomprising such semiconductor packages mounted on printed circuitboards.

For example, semiconductor packages have been shifting from the DIP(dual in-line package) and other surface mounted types to flip-chipmounted types providing the pad electrodes of semiconductor chips withbumps made of solder, gold, etc. and connecting the chips to the circuitboards through the bumps in a state where the surfaces provided withbumps face the boards (face down).

Further, types forming multilayer interconnects also known asreinterconnect layers on the semiconductor chips and the complicatedtypes known as “system-in-packages (SiP)” packaged by burying coils orother passive devices or other semiconductor chips between insulatinglayers insulating the reinterconnect layers formed on the semiconductorchips are being developed.

As the method of producing a semiconductor package burying othersemiconductor chip between the insulating layers insulating thereinterconnect layers formed on semiconductor chip, the method of diebonding other semiconductor chip (hereinafter sometimes simply referredto as “semiconductor chip”) on semiconductor chip serving as a substrate(hereinafter sometimes simply referred to as “substrate”) and forminginsulating layers comprised of resin layers containing thereinterconnect layers covering the same is widely known.

In this method of producing a semiconductor package, as the method ofdie bonding the semiconductor chip on the substrate, the method ofgrinding down the wafer from the back side when the semiconductor chipis supplied in the wafer state before dicing, laminating a die-attachfilm (adhesive film) in the wafer state, dicing the wafer to obtain theindividual semiconductor chips, and mounting the obtained semiconductorchip to the substrate face up or face down is widely used.

On the other hand, when the semiconductor chips are supplied in a statealready separated into individual units, usually they are supplied on 4inch diameter chip trays and are mounted face up or face down on thesubstrates of the SiPs by die bonding. Here, there are restrictionsderived from the multiple layers in the wafer state and the resinforming the SiPs etc., so the semiconductor chips of the SiP have to bereduced in thickness to about 50 μm. The individually separatedsemiconductor chips are reduced in thickness by the following procedure.That is, a package use monitor wafer is attached to the center of aprotective tape for use in grinding down the semiconductor chips, theindividually separated semiconductor chips are arranged around it, andthe chips are ground down while monitoring the thickness of the monitorwafer.

The ground down thin semiconductor chip is then reattached to transfersheet etc. for mounting on the substrate and supplied to a die bonder.Here, for example when using an insulating paste in a die bonder forbonding face up, a scrubbing operation becomes necessary to make thepaste a uniform thickness. However, thin semiconductor chip lacksstrength and is liable to break, so cannot be scrubbed. Therefore, thinsemiconductor chip cannot be bonded by paste. Accordingly, thinsemiconductor chip is bonded using a uniform thickness die-attach film.

A die-attach film, as shown in the schematic view of FIG. 1, is usuallysupplied in the form of a roll R1. This has a width W1 far greater thanthe width of the semiconductor chip, so at the time of actual use, asshown in the schematic view of FIG. 2, it is cut corresponding to thewidth W2 of the semiconductor chip to obtain the roll R2. As shown inthe schematic view of FIG. 3, the film is fed out and cut from the rollR2 by a cutter 100 into the size of the semiconductor chip. Thesemiconductor chip 102 is then bonded to the thus obtained predeterminedsized piece of die-attach film 101 using a collet 103. The thus obtainedsemiconductor chip with the piece of die-attach film bonded to it istransported by a suction collet to the substrate and mounted on thesubstrate.

In the above method however, it is necessary to prepare a roll cut tothe width of the chip. When handling several types of semiconductorchips of different sizes, the loss ends up becoming greater. Further,precise bonding to the semiconductor chip after cutting is difficult.The piece of die-attach film easily sticks out from the semiconductorchip. When actually sticking out, the part where the piece of die-attachfilm stick out lacks photosensitivity and via holes cannot be formed, sointerconnect defects are liable to occur.

Summarizing the problems to be solved by the invention, when mounting anindividually separated thin semiconductor chip on a substrate, the lossof the die-attach film (adhesive film) is great and the piece ofdie-attach film sticks out from the semiconductor chip to easily causean interconnect defect.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method of producing asemiconductor package enabling a sheet-like adhesive film to be used asit is and thereby reducing loss and enabling mounting without the pieceof the adhesive film sticking out from the semiconductor chip and anapparatus for producing a semiconductor package and an adhesive film foruse with that method.

According to a first aspect of the present invention, there is provideda method of producing a semiconductor package mounting a semiconductorchip on a substrate by an adhesive film, comprising the steps of formingcutting-off notches in the adhesive film provided on a support film fromthe adhesive film side down to a surface or a midway depth of thesupport film to cut-off the adhesive film into predetermined sizedpieces; stretching the support film to separate the adhesive film intothe cut individual pieces; attaching a semiconductor chip to the cutindividual piece of the adhesive film; and mounting the semiconductorchip on the substrate by the piece of adhesive film.

According to a second aspect of the present invention, there is providedan apparatus for producing a semiconductor package mounting asemiconductor chip on a substrate by an adhesive film, comprising asupport which supports a support film on which an adhesive film havingcutting-off notches into a plurality of pieces having a predeterminedsize is provided; a pushup tool having a rounded tip which pushes up thesupport film from the back side of the surface on which the adhesivefilm is provided so as to stretch the support film and separate theadhesive film into the cut individual pieces; a suction unit which picksup the semiconductor chip by suction and attaches the semiconductor chipto the individual cut piece of adhesive film and which picks up bysuction the semiconductor chip on which the piece of adhesive film isattached and mounts the semiconductor chip on the substrate.

According to a third aspect of the present invention, there is providedan adhesive film for bonding a semiconductor chip to a substrate,provided on a support film, and having cutting-off notches from theadhesive film side down to a surface or a midway depth of the supportfilm, for cutting-off the adhesive film into a plurality of pieceshaving a predetermined size.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention willbecome clearer from the following description of the preferredembodiments given with reference to the attached drawings, wherein:

FIG. 1 is a schematic view of the configuration of a die-attach film ofthe related art;

FIG. 2 is a schematic view of the configuration of a die-attach film ofthe related art;

FIG. 3 is a schematic view of the steps of production of semiconductorpackages according to the related art;

FIG. 4 is a cross-sectional view of a die-attach film according to afirst embodiment of the present invention at the time of supply (beforeuse);

FIG. 5 is a schematic view of the configuration of a regular blade inthe first embodiment of the present invention;

FIG. 6 is a schematic view of the steps of production of a semiconductorpackage according to the first embodiment of the present invention;

FIG. 7 is a plan view of cuts made in a die-attach film according to thefirst embodiment of the present invention;

FIG. 8 is a schematic view of the steps of production of a semiconductorpackage according to the first embodiment of the present invention;

FIG. 9 is a schematic view of the steps of production of a semiconductorpackage according to the first embodiment of the present invention;

FIG. 10 is a schematic view of the steps of production of asemiconductor package according to a second embodiment of the presentinvention;

FIG. 11 is a schematic view of the steps of production of asemiconductor package according to a third embodiment of the presentinvention;

FIG. 12 is a schematic view of the steps of production of asemiconductor package according to the third embodiment of the presentinvention;

FIG. 13 is a schematic view of the steps of production of asemiconductor package according to the third embodiment of the presentinvention;

FIG. 14 is a schematic view of the steps of production of asemiconductor package according to the third embodiment of the presentinvention;

FIG. 15 is a schematic view of the steps of production of asemiconductor package according to the third embodiment of the presentinvention;

FIG. 16 is a schematic view of the steps of production of asemiconductor package according to the third embodiment of the presentinvention; and

FIG. 17 is a schematic view of the steps of production of asemiconductor package according to the third embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the method of producing a semiconductorpackage, an apparatus for producing a semiconductor package, and anadhesive film according to the present invention will be described indetail below while referring to the attached figures.

First Embodiment

The semiconductor package according to the present embodiment is an SiPtype semiconductor package comprising semiconductor chip serving as asubstrate (hereinafter sometimes simply called “substrate”) on whichother semiconductor chip (hereinafter sometimes simply called“semiconductor chip”) is die bonded and covered by insulating layerscomprising resin layers including reinterconnect layers. Thesemiconductor chip and substrate are provided with predeterminedsemiconductor devices and electronic circuits and are connected witheach other by the reinterconnect layers whereby the semiconductor chipand substrate are joined.

Such semiconductor chip is supplied in individually separated state andis reduced in thickness to about 50 μm for being buried in theinsulating layers. This thinning process is performed for example byattaching a height gauge monitor wafer to the center of a protectivetape for use for grinding down the semiconductor chips, attachingindividually separated semiconductor chips around it, and monitoring thethickness of the monitor wafer while grinding them down. The thusthinned semiconductor chip is mounted on the substrate face up by adie-attach film (adhesive film) and set into the SiP.

FIG. 4 is a cross-sectional view of a die-attach film at the time ofsupply (before use). For example, a 10 to 50 μm thick die-attach film 10comprised of an epoxy resin or other adhesive resin is suppliedsandwiched between a 50 μm thick support film 11 comprised ofpolyethylene terephthalate (PET) etc. and a 20 μm thick cover film 12comprised of the same PET. At the time of use, first, the cover film 12is peeled off from the die-attach film 10, the semiconductor chip to bebonded is attached to the die-attach film 10, then the support film 11is peeled off and the die-attach film is used to bond the semiconductorchip to the substrate.

Next, the method of producing a semiconductor package by mountingsemiconductor chip on a substrate by the above die-attach film accordingto the present embodiment will be explained. First, the cover film 12provided on the die-attach film 10 is peeled off, cuts are made into thedie-attach film 10 provided on the support film 11, then the die-attachfilm 10 is separated into predetermined sized pieces.

Here, to make cuts in the die-attach film, for example a regular blade30 of the configuration shown in the schematic view of FIG. 5 is used.This is configured by a disk-shaped base at the outer rim of which a diecutting blade is provided. FIG. 5 corresponds to a cross-sectional viewof a plane perpendicular to the surface of a disk. For example, thelength L of the blade is about 0.5 μm, and the tip angle θ of the bladeis 7 to 13°. The surface is formed with a fluorine-based film so as helpprevent sticking by the resin ingredient forming the die-attach filmwhen cutting the die-attach film.

When making cuts into the die-attach film 10, as shown in the schematicview of FIG. 6, in the die-attach film 10 provided on the support film11, cutting-off notches 10 a are formed using the regular blade 30 fromthe die-attach film 10 side down to a depth (D) midway in the supportfilm 11. That is, the die-attach film 10 is cut so as to preventcomplete cutting of the support film 11. The depth D of the cutting-offnotches 10 a made into the support film 11 is for example 10 μm. Whenmaking cuts into the die-attach film 10 in this way, for example asshown in the plan view of FIG. 7, the cutting-off notches 10 a are madein a checkerboard manner corresponding to the size of the semiconductorchip. When cutting the die-attach film into predetermined sized piecesby this method, even if supplying a sheet-like die-attach film from aroll having a width larger than the width of the semiconductor chip,cutting into predetermined size becomes possible and any sized pieces ofdie-attach film can be supplied.

At this time, it is preferable to cut the film to pieces of size notexceeding the size of the semiconductor chip even after stretching theadhesive film in the later step of stretching the support film. That is,the size of the cut out piece of the die-attach film is made smallerthan the size of the semiconductor chip bonded using it. This is becausewhen stretching the support film in the later step to separate theadhesive film into the individual pieces of die-attach film, the pieceof the die-attach film itself also ends up being stretched. Thispractice therefore prevents it from sticking out from the semiconductorchip even in the stretched state. Specifically, the piece is cut to beabout 50 μm smaller than the two sides of the semiconductor chip.

Next, the support film 11 is stretched to separate the adhesive film 10into the individual pieces. In the present embodiment, as the apparatusfor producing a semiconductor package performing this step, the diebonder shown in the schematic view of FIG. 8 is used. The die bonder ofFIG. 8 is an apparatus for producing a semiconductor package mountingsemiconductor chip on substrate by a die-attach film and has a supportring (support part) 31 called a “dicing ring”, a pushup collet (pushuptool) 32, and a suction collet (suction unit) 33. The support ring 31supports the support film 11 on which the die-attach film 10 cut topredetermined sized pieces in the above step is provided and is set at awafer chuck in that state. The pushup collet 32 has a rounded tip andpushes up the support film 11 from the back side of the surface wherethe die-attach film 10 is provided so as to stretch the support film 11and separate the die-attach film 10 into the cut individual pieces atthe cuts 10 a. The pushup collet 32 is provided instead of the pushupneedles usually provided at a die bonder for pushing up thesemiconductor chip and peeling it off from the support film and enablesutilization of existing apparatus with the minimum modification. Thedistance of separation between pieces of the die-attach film 10 due tothe pushup is made about 50 to 100 μm and the radius of curvature of thetip of the pushup collet 32 is made about 10 times the size of thesemiconductor chips. The suction collet 33 applies suction from asuction hole 32 a and can pick up a semiconductor chip 21 by suction.This will be explained later.

By using the die bonder and pushing up the support film 11 by the pushupcollet 32 from the back side of the surface where the die-attach film 10is provided, the support film 11 can be stretched so as to separate theadhesive film into the cut individual pieces at the cuts 10 a.

Next, semiconductor chip reduced in thickness to about 50 μm is attachedto the cut individual piece of the die-attach film 10, then thesemiconductor chip 21 is mounted on substrate 20 by the piece of thedie-attach film 10. This step is performed using the suction collet 33of the die bonder. The suction collet 33 has the function of applyingsuction from a built-in suction hole 33 a to pick up a semiconductorchip 21 by suction. As shown in the schematic view of FIG. 8, thesemiconductor chip 21 is attached to the individually separated piece ofthe die-attach film 10 and, as shown in the schematic view of FIG. 9,the semiconductor chip 21 with the die-attach films 10 attached to it ispicked up by suction and mounted on the substrate 20. The suction collet33 includes a not shown pulse heater. When for example attaching thesemiconductor chip 21 on the die-attach film 10, it is heated at atemperature of 60 to 80° C. for about 3 seconds. Due to this, it ispossible to prevent the occurrence of voids in the die-attach film 10.At this time, the weighting applied to the suction collet is made forexample 1N per chip. Here, to attach the semiconductor chip 21 to thedie-attach film 10, the position of the semiconductor chip is imageprocessed before pushing up the cut positions which are made to thedie-attach film 10 by the pushup collet and the obtained data is usedfor positioning for the attachment. Further, when mounting thesemiconductor chip 21 on which the die-attach film 10 are attached onthe substrate 20 as well, it is heated by a pulse heater at atemperature of 60 to 80° C. for about 3 seconds. Further, as post-baketreatment, each substrate is heated to a temperature of 140 to 160° C.to enable complete bonding.

As subsequent steps, for example, the semiconductor chip 21 die-bondedon the substrate 20 by the piece of the die-attach film 10 is covered bythe formation of reinterconnect layers for electrically connecting thesemiconductor chip 21, substrate 20, and coil and other passive devicesand insulating layers comprising resin layers including the same so asto produce SiP type semiconductor package.

According to the method of producing a semiconductor package of thepresent embodiment, by introducing a step of bonding a piece ofdie-attach film to thinned, individually separated semiconductor chipand a step of mounting it on substrate, it becomes possible to attachthe die-attach film to any shape of chip. Further, by introducing themethod of forming cutting-off notches in the die-attach film in thesheet form, it is possible to handle different shapes by just changingthe pushup tool section of the die bonder corresponding to usual wafers.Further, the die-attach film and semiconductor chip can be aligned at ahigh precision by employing a die bonder and therefore protrusion of thepiece of the die-attach film from the semiconductor chip can be kept toa minimum. In this way, according to the method of producingsemiconductor package of the present embodiment, it is possible to use asheet-like adhesive film as it is, so there is little loss and mountingis possible without the piece of adhesive film sticking out from thesemiconductor chip. Therefore, it is possible to produce a semiconductorpackage while suppressing the interconnect defect.

According to the apparatus for producing semiconductor package of thepresent embodiment, it is possible to realize the method of producing asemiconductor package of the present embodiment. Further, it is possibleto separate the sheet-type adhesive film having cutting-off notches inaccordance with the semiconductor chip into the individual piece ofadhesive film and mount the semiconductor chip on the substrate by thepiece of adhesive film.

The die-attach film of the present embodiment can be used in the methodof producing a semiconductor package of the present embodiment andenables the semiconductor chip to be bonded on a substrate withoutsticking out from the semiconductor chip.

Second Embodiment

The method of producing a semiconductor package according to the presentembodiment is substantially the same as the first embodiment, butinstead of using the regular blade 30 comprising the disk-shaped baseprovided at its outer rim with a die cutting blade in the step ofcutting the die-attach film into pieces of predetermined sizecorresponding to the individual semiconductor chip, as shown in theschematic view of FIG. 10, for the die-attach film 10 provided on thesupport film 11 cutting-off notches 10 a are formed by a laser beam 35of a wavelength absorbed by the die-attach film 10 and substantially notabsorbed by the support film 11 comprising PET etc. from a laser lightsource 34. For example, it is possible to use a YAG laser or CO₂ laser.The laser beam 35 passes through the support film 11 and is notabsorbed, so it is possible to form cutting-off notches in thedie-attach film 10 provided on the support film 11 from the die-attachfilm 10 side down to the surface of the support film 11 and cut thedie-attach film 10 into predetermined sized pieces. Aside from this, itis possible to follow substantially the same procedure as the firstembodiment.

According to the method of producing a semiconductor package of thepresent embodiment, in the same way as the first embodiment, it ispossible to use a sheet-like adhesive film as it is, so there is littleloss and mounting is possible without the piece of adhesive filmsticking out from the semiconductor chip. Therefore, it is possible toproduce a semiconductor package while suppressing the interconnectdefect.

Third Embodiment

The method of producing a semiconductor package according to the presentembodiment is substantially the same as that of the first embodiment,but it differs from it in that in the step of stretching the supportfilm to separate the adhesive film into the individual cut pieces, nodie bonder of FIG. 8 is used, that is, the following method is used forseparation.

The method of producing a semiconductor package according to thisembodiment will be explained below. First, as shown in the schematicview of FIG. 11, a support film (UV sheet) 41 is attached to a supportring (wafer ring) 40, then a rolling transfer method or other techniqueis used to transfer and bond the die-attach film 10 with the supportfilm 11 to the support film 41.

Next, as shown in the schematic view of FIG. 12, the support film 11 ispeeled off from the die-attach film 10. With this, only the die-attachfilm 10 is present on the support film 41.

Next, a Thomson bar is used to form cutting-off notches in thedie-attach film 10 provided on the support film 41 from the die-attachfilm 10 side down to a depth in the middle of the support film 41 forcut-off the die-attach film 10 to predetermined sized pieces. That is,first, as shown in the schematic view of FIG. 13, cutting-off notches 10a parallel to one direction are formed. Next, as shown in FIG. 14, thenotch direction is rotated 90 degrees and cutting-off notches 10 a areformed in another direction substantially perpendicular to that onedirection for cutting-off the film into rectangular shapes.

In cutting the die-attach film 10, care is taken not to completely cutthe support film 41. The die-attach film 10, in the same way as thefirst embodiment, is cut into pieces smaller in size in advanceconsidering the fact that they becomes larger in the followingstretching step.

Next, as shown in the schematic view of FIG. 15, the support film isattached to the support ring, then an expander is used to stretch thesupport film 41 in the radial directions from the center of the supportring 40. At this time, the cut die-attach film 10 is also similarlystretched. According to this, the intervals between the pieces of thedie-attach film 10 are also stretched and the film is separated into theindividual pieces of die-attach film 10. Here, the distance between cutpieces of the die-attach film 10 is set to become at least 0.3 mm.

Next, as shown in the schematic view of FIG. 16, semiconductor chip 21reduced in thickness in advance and placed on a stackable andautomatically feedable waffle tray 42 are supplied. Using a not showncollet etc., the semiconductor chip 21 is attached to the individuallyseparated piece of the die-attach film 10 with reference to their outershapes. By using their outer shapes as reference, the mounting precisionbecomes about ±15 μm. Here, the center of gravity and angle of each chipare checked by image processing etc. and the chip is adjusted to thesuitable direction for bonding. The size of a semiconductor chip 21 isfor example 3.55 mm×4.7 mm with a thickness of 0.025 mm.

Next, as shown in the schematic view of FIG. 17, the support ring 40 isheld and moved and a heater 43 is used to heat the piece of thedie-attach film 10 to a predetermined temperature for a predeterminedtime through the support film 41. After finishing the heating, the filmis set in the die bonder as it is, where the semiconductor chip 21 towhich the piece of the die-attach film 10 is attached is peeled off fromthe support film 41 and die bonded to the substrate. The rest of thesteps are the same as in the first embodiment.

According to the method of producing a semiconductor package of thepresent embodiment, it is possible to use a sheet-like adhesive film asit is in the same way as in the first embodiment, so the loss is smalland mounting is possible without the pieces of the adhesive filmsticking out from the semiconductor chip. Therefore, the interconnectdefect can be suppressed in production.

The present invention is not limited to the above examples. For example,the SiP type semiconductor package may have embedded in the resin layersformed on the semiconductor chip serving as the substrate not only othersemiconductor chip, but also coil and other passive devices and otherelectronic devices.

The method of production of a semiconductor package of the presentinvention may be applied to the production of a system-in-package typesemiconductor package. Further, the apparatus for producing asemiconductor package of the present invention may be applied to anapparatus for producing a system-in-package type semiconductor packagefor working the method of producing a semiconductor package of thepresent invention. Further, the die-attach film of the present inventionmay be applied to a die-attach film for die bonding a semiconductor chipon a substrate for working the method of producing a semiconductorpackage of the present invention.

While the invention has been described with reference to specificembodiments chosen for purpose of illustration, it should be apparentthat numerous modifications could be made thereto by those skilled inthe art without departing from the basic concept and scope of theinvention.

The method of producing a semiconductor package of the present inventionenables a sheet-like adhesive film to be used as it is, so reduces loss.Further, it enables mounting without the piece of adhesive film stickingout from the semiconductor chip, so a semiconductor package can beproduced while suppressing interconnect defects.

The apparatus for producing a semiconductor package of the presentinvention enables the method of producing a semiconductor package of thepresent invention to be realized and enables sheet-like adhesive filmhaving cutting-off notches corresponding to the semiconductor chip to beseparated into individual pieces of adhesive film and mounting of thesemiconductor chip on a substrate by the piece of adhesive film.

The adhesive film of the present invention can be used in the method ofproducing a semiconductor package of the present invention and enables asemiconductor chip to be bonded to a substrate without sticking out ofthe film from the semiconductor chip.

1-7. (canceled)
 8. An apparatus for producing a semiconductor packagemounting a semiconductor chip on a substrate by an adhesive film,comprising: a support which supports a support film on which an adhesivefilm having cutting-off notches into a plurality of pieces having apredetermined size is provided; a pushup tool having a rounded tip whichpushes up said support film from the back side of the surface on whichsaid adhesive film is provided so as to stretch said support film andseparate said adhesive film into the cut individual pieces; a suctionunit which picks up said semiconductor chip by suction and attaches saidsemiconductor chip to the individual cut piece of adhesive film andwhich picks up by suction said semiconductor chip on which said piece ofadhesive film is attached and mounts the semiconductor chip on saidsubstrate.
 9. (canceled)